Trade lanes are the major travel system within most civilized systems, akin to a highway. They consist of two "rings" each composed of four brackets. It is through these that the ship must go through. Once activated with the dock maneuver, each bracket fires out an energy beam which combines with the others to form the transportation. Brackets are usually placed every 7 kilometers.
Once in the docking process, your ship is vunerable to enemy fire, so the best tactic for escaping into a trade lane is to locate the entry ring (designated by flashing green lights on the brackets), fly almost into the ring and activate "Dock". This gives a mere one second delay until your ship is flung into the trade lane and out of range, which should be quick enough to avoid destruction. A tactic for getting a kilometer or so distance boost coming out of a trade lane is to drop out of a lane right before the second to last ring, then get back in. It will take about 6 kilometers to fully accelerate so the trade lane cannot decelerate fast enough in the remaining kilometer and will give a huge boost, which is very useful for escaping authorities when carrying contraband.
A trade lane will sometimes be disrupted, with one ring disabled and a squadron of pirates loitering nearby. In this case you will need to wait for the ring to reboot. You can disrupt trade lanes yourself by blasting the ring. Ironically, when a ring reboots, the pirates actually can't turn it back off; their shots pass through the gap between the two rings.